JP2005069114A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a canned motor pump and a magnet pump which are of high efficiency, are simple in structure, are small-sized and compact, with excellent productivity. <P>SOLUTION: This pump comprises: a motor rotor 17 rotating in a liquid in response to a rotating magnetic field of a stator 11 of a motor part 1; a rotor casing 13 covering therein the liquid around the rotor 17; and a main shaft 24 transmitting a rotation force of the rotor 17 to a pump part 2. In the pump, a slide bearing supporting the main shaft 24 is provided integrally with the rotor casing 13. By integrally providing the slide bearing with the rotor casing 13, the slide bearing and the rotor casing 13 are integral parts, thereby eliminating a press fitting operation at assembling of the pump. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pump having a rotor that rotates in a liquid corresponding to the rotating magnetic field of a stator of a drive motor, and has high efficiency, a simple structure, a small size, a compact size, and good productivity. The present invention relates to a canned motor pump and a magnet pump.

  Many of the canned motor pumps and magnet pumps are made of a resin material such as polypropylene (PP) in a rotor casing that encloses liquid around the rotor. The reason for this is that if it is made of a metal material, an eddy current flows during operation to inhibit the efficiency, and the resin is relatively excellent in corrosion resistance. In many cases, a carbon sliding bearing or the like is press-fitted and fixed to the rotor casing, and a rotating shaft made of alumina ceramic, for example, is supported.

  In the configuration in which a carbon sliding bearing or the like is press-fitted and fixed to the rotor casing as described above, there is a concern that the press-fitting portion may be loosened due to a difference in linear expansion coefficient between the rotor casing and the bearing, for example, when the liquid temperature is high. For this reason, it is necessary to increase the press-fitting allowance or to devise a detent shape. However, even if the press-fitting allowance is increased, there is a possibility that the rotor casing made of the resin material creeps and loosens. In addition, there is a problem that productivity is adversely affected because it is necessary to assemble while adjusting the press-fitting angle for providing a non-rotating shape (key & key groove).

JP 2002-138990 A

  In order to prevent loosening of the press-fitting part due to the difference in the linear expansion coefficient between the conventional rotor casing and the bearing as described above, a method for increasing the press-fitting allowance or providing a non-rotating shape (key & key groove, etc.) There is a problem that creeping causes loosening and productivity is impaired. An object of the present invention is to solve such problems and to provide a canned motor pump and a magnet pump that are highly efficient, have a simple structure, are small and compact, and have good productivity.

  In order to solve the above-mentioned problem, the invention described in claim 1 includes a rotor that rotates in a liquid corresponding to a rotating magnetic field of a stator of a drive motor, a rotor casing that encloses liquid around the rotor, A pump having a rotating shaft that transmits the rotational force of the rotor to a pump unit is characterized in that a sliding bearing for supporting the rotating shaft is provided integrally with the rotor casing. By providing the slide bearing integrally with the rotor casing in this manner, the slide bearing and the rotor casing become an integral part, so that the press-fitting work at the time of pump assembly can be eliminated.

  According to a second aspect of the present invention, in the pump according to the first aspect, the rotor casing provided with the sliding bearing portion is made of a single material. When the rotor casing having the sliding bearing portion is made of a single material, specifically, a material in which PEEK (polyether, ether, ketone), which is a resin, is filled with Teflon (registered trademark) is used. Since the material has heat resistance and is excellent in strength, it is suitable as a material for a rotor casing that is a pressure vessel. At the same time, it is filled with Teflon (registered trademark), for example against a rotating shaft made of stainless steel. An effective sliding bearing can be constructed.

  According to a third aspect of the present invention, in the pump according to the first or second aspect, the sliding bearing is made of a first resin material, and the sliding bearing is a second resin having a molding temperature lower than that of the first resin material. It is characterized by being insert-molded so as to be covered with a resin material. Thus, the rotor which is a pressure vessel is employ | adopted as the structure which insert-molds so that the sliding bearing manufactured with the 1st resin material may be covered with the 2nd resin material whose molding temperature is lower than the 1st resin material. The casing material is a relatively inexpensive resin material when the operating pressure and temperature are low, and only the sliding bearing portion can be made of the above-mentioned PEEK filled with Teflon (registered trademark). It becomes possible to reduce the entire manufacturing cost.

  The pump of the present invention can provide a canned motor pump and a magnet pump that are highly efficient, have a simple structure, are small and compact, and have good productivity.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing a configuration example of a pump according to the present invention. This pump is a single-stage centrifugal motor pump having a specific speed Ns (m ³ / min, m, min ⁻¹ ) at the maximum efficiency point flow rate of 160, for example, and the outer diameter of the impeller is 20 mm, for example. The maximum wetting edge diameter of the rotor is 10 mm, the radial gap δ formed outside the maximum wetting edge outer diameter of the motor rotor is 1 mm, and the axial length of the maximum wetting edge outer diameter of the motor rotor is 25 mm.

  This pump includes a motor unit 1 and a pump unit 2. The motor unit 1 is a so-called DC brushless motor, and structurally falls within the category of a canned motor. The motor stator 11 is accommodated in a motor frame 12 made of cup-shaped aluminum die casting. A cup-shaped rotor casing 13 made of PEEK is provided on the inner peripheral side of the motor stator 11, and the flange 13 b is sandwiched between the motor frame 12 and the resin pump casing 14. A PEEK bearing bracket 15 is sandwiched between the rotor casing 13 and the pump casing 14, and a part of the bearing bracket 15 functions as a load-side radial bearing and a thrust bearing.

  In the motor rotor 17, a neodymium permanent magnet 19 is provided on the outer periphery of a metal magnetic yoke 18, and a cup-shaped rotor outer cover 20 and the rotor are disposed so as to surround the yoke 18 and the permanent magnet 19. An inner cover 21 is provided and sealed with seal members 22 and 23 such as O-rings. By adopting such a configuration, the permanent magnet 19 and the magnetic yoke 18 are completely cut off from the pump-handed liquid, so that rust does not occur. A main shaft 24 is inserted into the shaft core portion of the motor rotor 17. The main shaft 24 is made of an austenitic stainless alloy and has a diameter of about 1.5 mm, for example, and shaft sleeves 25 and 26 are attached to both ends. Reference numeral 28 denotes a retaining ring that stops the movement of the rotor outer cover 20 in the axial direction.

  A closed type (equipped with a front shroud) impeller 27 of the centrifugal pump unit 2 is attached to one end of the main shaft 24. The impeller 27 has a diameter of, for example, 20 mm, and the hole (main shaft through hole) through which the main shaft 24 of the impeller 27 passes is a perfect circle of about 1.5 mm on the suction mouse side of the impeller 27, and the diameter of the anti-suction mouse side is 3 mm. A shaft sleeve 25 of about 5 mm can be inserted. The shaft sleeve 25 is prevented from rotating relative to the impeller 27 by, for example, chamfering the main shaft through hole of the impeller 27 and a part of the shaft sleeve 25 with a diameter of about 3.5 mm (distance between the two surfaces is about 3 mm). To do. The impeller 27 is manufactured by injection molding a resin material such as PPS (polyphenylene sulfide), and the shaft sleeves 25 and 26 are manufactured by a ceramic material such as alumina.

  The shaft sleeves 25 and 26 are prevented from rotating with respect to the main shaft 24 of the motor rotor 17 by, for example, chamfering the main shaft through hole of the motor rotor 17 and part of the shaft sleeves 25 and 26 with respect to a diameter of about 3.5 mm. The distance between the two surfaces is about 3 mm). The outer diameter portion of the shaft sleeve 26 forms a sliding surface with the inner diameter of the bearing portion of the bearing bracket 15. Thrust disks 16 and 16 are sandwiched between the rotor inner cover 21 and the shaft sleeve 25 and between the impeller 27 and the shaft sleeve 25 of the motor rotor 17. The thrust disks 16 and 16 are secured to the shaft sleeve 25 in the same manner as the shaft sleeves 25 and 26 are prevented from rotating with respect to the main shaft 24, and slide between the axial end surfaces of the bearing portions of the bearing bracket 15. Bearing thrust load. A portion corresponding to the shaft sleeve 26 at the end of the main shaft 24 on the counter pump side of the rotor casing 13 is provided integrally with the rotor casing 13 to support a load in the radial direction.

  A T-shaped forged portion 24a forged into a T shape is formed at the end of the main shaft 24 on the impeller 27 side, and an E-shaped retaining ring 29 is attached to the end of the impeller to attach the impeller. Members such as 27 do not fall off the main shaft 24. This fixing means does not tighten the member in the axial direction like a screw, but simply restricts the movement of the member in the axial direction. The present invention has a structure in which there is no problem even if there are some gaps and play in the axial direction between the members, and it is possible to use fixing means of these simple configurations. Therefore, productivity is also good.

  Further, if an element (not shown) such as a coil spring is sandwiched between the fixing means (E-shaped retaining ring 29) and the shaft sleeve 26, the fixing means (T-shaped) of the shaft end portions 24a and 24b of the main shaft 24 is obtained. Since the member sandwiched between the forged molded portion 24a and the E-shaped retaining ring 29) does not move while generating a rattling noise, no noise is generated. In addition, since the groove | channel is provided in the boss | hub part end surface of the impeller 27 corresponding to the T-shaped forge molding part 24a of the edge part at the side of the impeller 27 of the main shaft 24, it is transmitted to the impeller 27 from the shaft sleeve 25. The rotating torque transmitted to the main shaft 24 is also transmitted.

  The pump casing 14 has a cup shape and is formed of a resin material such as PPS. A suction nozzle 14 a is provided at the cup-shaped bottom of the pump casing 14, and a discharge nozzle 14 b is provided on the side surface. Further, the inner surface of the cup-shaped open portion of the pump casing 14 is fixed to the outer peripheral portion of the rotor casing 13 via a seal member 30 such as an O-ring to constitute a sealed container. Further, a fluororesin liner ring 31 is provided at the cup-shaped bottom portion of the pump casing 14 to form a minute gap with the outer peripheral portion of the suction mouth of the impeller 27. The pump casing 14 and the motor frame 12 are fixed with bolts with the rotor casing 13 interposed therebetween.

  Note that a socket 34 is connected to the suction nozzle 14 a of the pump casing 14 by a stopper 32, and an inflow pipe 35 into which the handling liquid flows is connected to the socket 34. A seal member 33 such as an O-ring is interposed between the pump casing 14 and the socket 34. A socket 38 is connected to the discharge nozzle 14 b of the pump casing 14 by a stopper 36, and an outflow pipe 39 through which the handling liquid flows out is connected to the socket 38. A seal member 37 such as an O-ring is interposed between the pump casing 14 and the socket 38. Reference numeral 40 denotes a motor frame band.

  The handling liquid sucked from the suction nozzle 14 a of the pump casing 14 is guided into the impeller 27 from the suction mouse of the impeller 27, and is pressurized as the impeller 27 rotates, and passes through the discharge passage of the pump casing 14. It is discharged from the discharge nozzle 14b. A part of the handling liquid is introduced into the rotor casing 13 and used for lubricating the bearing portion and cooling the motor portion 1. As described above, in the present invention, since the radial gap δ formed outside the maximum diameter of the wet edge of the motor rotor 17 is 1 mm, which is larger than that of a general canned motor, the liquid to be handled is from the outer circumferential gap of the motor rotor 17. It is supplied to the sliding surface of the bearing without being affected by the viscosity of the handling liquid. As a result, since there is no need to provide a through hole in the main shaft 24, the thickness of the main shaft 24 can be designed to be narrow to its strength limit.

  Since the pump according to the present invention is constructed by utilizing the shaft sleeves 25 and 26 as the sliding bearing for supporting the main shaft 24 as described above, it is substantially unnecessary to secure the strength against “torsion”. The shaft diameter can be set to a very small value because it is only necessary to ensure the strength against “and pull”. As a result, the boss diameter of the impeller 27 is kept small, and the ratio of the suction mouse diameter of the impeller 27 to the outer diameter of the impeller 27 can be optimized, so that the hydrodynamic efficiency of the impeller 27 is set to a good value. It becomes possible. Moreover, since the diameter of the motor rotor 17 can be suppressed to an extremely small value, the stirring loss accompanying the rotation of the motor rotor 17 can be reduced.

  Further, in the small pump as described above, the sliding bearing that supports the rotor casing 13 and the main shaft 24 that is the rotating shaft can be integrated, so that the press-fitting work at the time of assembling the pump can be eliminated, and a separate bearing component is manufactured. There is no need to do.

  FIG. 2 is a sectional view showing another configuration example of the pump according to the present invention. In FIG. 2, the parts denoted by the same reference numerals as those in FIG. The rotor casing 13 is made of PP (polypropylene), and insert molding is performed so that the PEEK bearing 41 manufactured in advance by injection molding is covered with the PP rotor casing 13. Since PEEK has a higher molding temperature than PP, there is no inconvenience of thermal deformation during insert molding. Furthermore, it is not necessary to perform alignment with a rotation stop at the time of press-fitting, and labor can be saved. The bearing bracket 15 is also insert-molded so that the PEEK bearing bracket 15 is covered with a PP rotor casing 13.

  Note that the outer peripheral portion of the PEEK bearing 41 is provided with a shape of “rotation stop” and “prevention of axial removal”. For this reason, for example, even when a pump is used with high-temperature liquid, there is a disadvantage that the bearing 41 rotates around the rotor casing 13 or the bearing bracket 15 due to a difference in linear expansion coefficient, or that the bearing 41 comes off in the axial direction. Absent.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible.

It is sectional drawing which shows the structural example of the pump which concerns on this invention. (Example 1) It is sectional drawing which shows the structural example of the pump which concerns on this invention. (Example 2)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor part 2 Pump part 11 Motor stator 12 Motor frame 13 Rotor casing 14 Pump casing 15 Bearing bracket 16 Thrust disk 17 Motor rotor 18 Yoke 19 Permanent magnet 20 Rotor outer cover 21 Rotor inner cover 22 Seal member 23 Seal Member 24 Main shaft 25 Shaft sleeve 26 Shaft sleeve 27 Impeller 28 Retaining ring 29 E-shaped retaining ring 30 Seal member 31 Liner ring 32 Stopper 33 Seal member 34 Socket 35 Inflow piping 36 Stopper 37 Seal member 38 Socket 39 Outflow piping 40 Motor Frame band 41 Bearing

Claims (3)

A rotor that rotates in liquid corresponding to a rotating magnetic field of a stator of a drive motor, a rotor casing that encloses liquid around the rotor, and a rotating shaft that transmits the rotational force of the rotor to a pump unit In the pump
A pump characterized in that a sliding bearing for supporting the rotating shaft is provided integrally with a rotor casing. The pump according to claim 1, wherein
A rotor characterized in that a rotor casing provided with the sliding bearing portion is made of a single material. The pump according to claim 1 or 2,
A pump characterized in that the sliding bearing is manufactured from a first resin material, and the sliding bearing is insert-molded so as to be covered with a second resin material having a molding temperature lower than that of the first resin material.

Images